FIX #62.
Method setArrayRange in jp_primitivetypes leaked memory in Python code as an
temporary PythonObject has not been refcounted properly.

Reworked single array element setters/getters to avoid a copy of the whole array
in worst case (use jni Get/SetArrayRange functions).
do not compile new setter on python 2.6 until memoryview is available somehow.
Merge pull request #66 from marscher/FIX_62

FIX #62.